Septic to aerobic sewage treatment conversion apparatus

ABSTRACT

Apparatus for use in converting septic bacterial-action sewage systems to aerobic sewage treatment systems. The apparatus consisting of a baffle to be positioned within a septic tank structure, having inlet and outlet ports, in an inclined position dividing the tank into an aeration chamber adjacent the inlet port and a settling chamber adjacent the outlet port. At least one air diffuser mounted adjacent the lowermost portion of the baffle which is spaced from the bottom of the tank and a conduit connecting the air diffuser to an air compressor. With this arrangement and with air issuing from the air diffuser countercurrent flows are imparted to the sewage in the aeration and settling chambers whereby continuous and complete aeration and mixing of the sewage in the tank is accomplished. In further aspect the baffle is provided with structure for returning scum from the surface of the liquid in the settling chamber to the aeration chamber, and in a further aspect the baffle is longitudinally extensible to accommodate various size tanks.

United States Patent [72] Inventor GeraldJ.Goodman Chomedey, Laval,Canada 211 App]. No. 878,844 [22] Filed Nov. 21, 1969 [45] Patented Dec.14, 1971 [73] Assignee Air Gest International Corp.

Montreal, Quebec, Canada [32] Priority Oct. 31, 1969 [33] Canada [31]066372 [54] SEPTIC T0 AEROBIC SEWAGE TREATMENT CONVERSION APPARATUS 7Claims, 3 Drawing Figs.

152 u.s.c1 210 195, 210/221 [51] 1nt.Cl C02c 1/12 [50] Field ot'Search210/195, 220, 221

{56] References Cited UNITED STATES PATENTS 2,574,685 11/1951 Baxteretal210 221 x 2,989,186 6/1961 Weis 210/221 X 3,161,590 12/1964 Weiset al.210/221 Primary ExaminerMichael Rogers Anorney-Browdy and NeimarkABSTRACT: Apparatus for use in converting septic bacterialaction sewagesystems to aerobic sewage treatment systems. The apparatus consisting ofa baffle to be positioned within a septic tank structure, having inletand outlet ports, in an inclined position dividing the tank into anaeration chamber adjacent the inlet port and a settling chamber adjacentthe outlet port. At least one air diffuser mounted adjacent thelowermost portion of the baffle which is spaced from the bottom of thetank and a conduit connecting the air diffuser to an air compressor.With this arrangement and with air issuing from the air diffusercountercurrent lflows are imparted to the sewage in the aeration andsettling chambers whereby continuous and complete aeration and mixing ofthe sewage in the tank is accomplished. in further aspect the baffle isprovided with structure for returning scum from the surface of theliquid in the settling chamber to the aeration chamber, and in a furtheraspect the baffle is longitudinally extensible to accommodate varioussize tanks.

Patwmmd ecu 14, 1971 3 Sheets-Sheet 5 FIG. 5

' SElP'llilC TO AEROBIC SEWAGE TREATMENT CONVERSION APPARATUS Thepresent invention relates to sewage treatment apparatus, andparticularly to apparatus for converting anaerobic septic tank systemsto efficient aerobic sewage treatment systems. The invention providesapparatus for installation in existing septic tank systems and also isalready constructed septic tanks prior to the installation of the tankin the ground.

By far the most common method of treating sewage in rural and outlyingdistricts and in some towns, is by way of septic tank systems. Thesewage when emptied into the septic tanks is decomposed by anaerobicbacterial action in a properly functioning septic system, but as it isestimated that a great majority of all septic systems now in use areineffectual in properly treating human wastes it is obvious that a moreeffective decomposition apparatus is required if further pollution oflakes and rivers is to be prevented.

As a result of recent Government investigation into pollution and thestartling discoveries made, it is clear that the pollution problem mustbe overcome quickly, both with respect to pollution caused by industryas well as by pollution caused by single and multiple family septicsystems.

With the pollution problem in mind it is the purpose of the presentinvention to provide apparatus at an economical cost to the purchaserfor convening existing anaerobic septic systems to aerobic sewagetreatment systems which is a much more efficient system as is wellknown.

Aerobic sewage treatment apparatus has been known for many years, but tothe best of applicants knowledge no attempt has yet been made to provideapparatus for installation in existing septic systems to convert thesystems to efficient sewage treatment systems.

In addition the invention relates to conversion apparatus which, wheninstalled, results in an aerobic sewage treatment system which is moreefficient in operation and yet cheaper in cost than existing aerobicsewage treatment systems now available on the market. With the apparatusof the invention installed in an existing septic tank, maximum treatingefficien' cy is obtained because the same apparatus which aerates thesewage also causes mixing and movement of sewage in the tank whereby allthe sewage introduced into the tank is sub jected to repeated settling,recirculation and aeration treatment before it is permitted egress fromthe tank in a satisfactorily treated condition.

Many attempts have been made to provide sewage treatment apparatus usingaeration features, but all have been generally unsatisfactory in theview of the private user, either for reasons of cost of installation ormaintenance or from the standpoint of overall inefficiency. Some knownsewage aeration apparatus include movable paddles or wheels in thesewage tank, and apparatus which includes these movable component partsis to be avoided in view of initial cost and maintenance and repairdemands.

Other known sewage treatment apparatus consists of a tank having twoinclined parallel and spaced apart baffles with an air diffuser systemtherebetween. The compressed air issuing from the diffuser results in acircular flow of the sewage in an aeration compartment and a drawing ofmaterial from a settling compartment for introduction into the aerationcompartment. However, in such systems one ofthe parallel baffles projectupwardly from the bottom of the tank and the other projects sewage fromthe top with the result that the the flow into the air bubble stream istaken directly and only from the settling compartment with the resultthat there is no intimate mixing of sewage from both of the compartmentsat that point where the air agitation action is the greatest, which isdirectly adjacent the diffuser. As a result, the mixing and aeration ofthe sewage in the tank is not as complete as possible with theconsequence that output from the tank is slowed and the capacity of thesystem is limited accordingly.

The present invention overcomes the aforesaid disadvantages by providinga sewage treatment apparatus for installation in existing septic systemswhich is economical in manufacture and which has no moving parts in thetank to malfunction, thus ensuring long life and trouble-free operation.in addition, the inventive apparatus provides for complete andcontinuous aeration of the sewage material in the tank and recycling andmixing of material from both an aeration chamber and a settling Chambertogether to cause complete aerobic decomposition of the sewage.

The main object of the present invention then is to provide apparatus toconvert septic systems dependent upon anaerobic bacterial action to muchmore efiective sewage treatment systems which treat human waste byaerobic action.

it is a further object to provide apparatus to convert septic systems tosewage treatment systems which is economical in manufacture andlong-lasting and durable in use and which requires little or nomaintenance.

it is still a further object of the invention to provide apparatus forinstallation into existing septic systems to convert the systems toefficient sewage treatment systems employing aerobic decomposition in amanner which promotes maximum treatment of the sewage by aeration.

It is a further object of the invention to provide a sewage treatmentsystem for human waste consisting of a tank divided by an inclinedbaffle into an aerating chamber and a settling chamber, with an airdiffuser provided adjacent the lowermost edge of the inclined baffle toprovide an upwardly moving flow of bubbles to aerate the sewage materialand to agitate and mix together sewage from the aeration chamber and thesolids drawn from the settling chamber as a result of displacement ofair by the diffuser to achieve maximum aeration of all of the sewage anddecomposition of all of the solids contained in the tank.

These and other objects of the invention will become ap parent from thefollowing description of the accompanying drawings wherein:

FIG. 1 illustrates in perspective view a standard septic tank havingportions of the side, end and top cut away for clarity, with theconversion apparatus of the invention positioned therein;

HO. 2 is a side view partially in section of the drawing shown in FIG.1; and

FIG. 3 is an enlarged perspective exploded view of the diffuser plateand air channel shown in FIGS. 1 and 2.

Referring now specifically to FIGS. 1 and 2, numeral 2 indicates astandard septic tank of generally rectangular or box design having aninlet 4 for water-home sewage and remotely positioned outlet 6fordecomposed sewage and supernatant liquid. A baffle 8 is usuallyprovided adjacent outlet 6 to prevent floating material from enteringoutlet 6. The tank 2 may be of metal, concrete or plastic construction,and may be of cylindrical or oval or other configuration, and thereference numerals 2, 4, 6 and 8 indicated above fairly represent a tankstructure presently in use in known septic bacterial-actiondecomposition systems.

in septic systems raw sewage is introduced into the tank via inlet Awhich is connected to a sewage source by suitable piping (not shown),and the sewage simply separates in the tank and the accumulating solidsawait slow bacterial action and decomposition, and as is so often thecase, the tank is overworked by the introduction of more sewage than canbe handled with the result that raw sewage simply passes through thetank after having undergone little or insufiicient treatment.

Aerobic decomposition action is of course quicker and more efficientthan the slow-working anaerobic bacterial treatment and the installationof inexpensive aerobic sewage treatment apparatus will result in morecomplete and efficient treatment of the Sewage while at the same timeincreasing the overall capacity of the system.

The conversion apparatus according to the present invention will now bedescribed.

The apparatus consists of a baffle 10 mounted in an inclined position asshown within the tank 2 by any suitable means, such as by self-tappingscrews, or bolts not shown) if the tank is of metal construction. Aswill be clearly seen in FIGS. l and 2 the baffle 10 is spaced a distanceabove the bottom 12 (FIG. 2) of the tank, and slots 14 in the uppermostportion of the baffle enable sewage to flow both beneath and over(through slots 14) the baffle. The lower edge of the slots 14 arepositioned just below the normal liquid level 16 in the tank. Of coursethe slots 14 could be eliminated with the top edge of the baffle beingpositioned just below the normal liquid level 16.

Inasmuch as existing septic tanks vary in width and shape and as it isnecessary that the bafl'le 10 project completely across the tank, thebaffle 10 may be longitudinally extensible as shown by portions 10 and10 to be adjustable to the width of the tank. The two portions 10 and 10may be slidably secured together in any suitable manner, but one simpleexpedient is simply to provide the longitudinal edges of one of theportions with U-turned flanges (not shown) to slidably receive the otherportion.

The guide plate or diffuser plate 18 and the bottom baffle 20 which arediscussed in more detail below are also extensibly adjustable to fit theinside of a tank as shown in the drawings.

Adjacent the bottom of baffle 10 a diffuser plate 18 (see also FIG. 3)is mounted parallel with, but spaced from (see FIG. 2) the lower planarsurface of the baffle. The difiuser plate 18 may be secured to thebaffle 10 by any suitable means such as by flanges, screws, welding orthe like (not shown).

On the surface of the diffuser plate 18 remote from the baffle an airchannel 22 (see also FIG. 3) is mounted and this channel is connected bytubing or by conduit 24 to an electric motor and air compressorcombination shown compactly at The surface of the diffuser plate 18facing the baffle 10 is provided with one or more longitudinal rows ofholes or apertures 28 (see FIG. 3) with the result that whenmotor-compressor 26 is activated a stream of bubbles issue from theapertures, and flow upwardly beneath the inclined baflle to promotecurrent flow in the sewage in the tank.

While an air channel 22 has been shown in the drawings as being providedonly on one portion 10 of the baffle it is quite apparent that adiffuser plate and air channel and a tubing connection tomotor-compressor 26 can also be secured to baffle portion 10'.

The positioning of the baffle 10 in the tank divides the tank into anaerating chamber 30 and a settling chamber 32.

The installation of baffle 10 and attachments including motor-compressor26 into a tank converts the tank into an aerobic sewage treatmentapparatus without additional equipment being necessary.

The motor and the compressor 26 may be mounted conveniently above thetank with an electric cable supplying electricity to the motor in theusual manner. While one motor only is contemplated, two could besupplied for standby service in the event of malfunction in the first,as the motor-compressor 26 is proposed to be in continuous service andnot intermittent.

In operation aqueous borne sewage enters the tank through inlet port 4into the aeration chamber 30. With motor-compressors 26 delivering airunder pressure (the actual pressure used depending on the size of theunit) through the apertures 28 a curtain of upwardly rushing air bubblesis formed between the underside of the inclined baffle l and thediffusion plate 18 with the result that an upwardly directed current ofbubbles and sewage material is created along the inclined baffle in thedirection of arrow 34 in FlG. 2. As a further result sewage material inthe aerating chamber 30 moves in the direction of arrows 36 and sewage:material in settling chamber 32 is drawn in the direction of arrows 38to pass together upwardly through the bubble force chamber between theinclined baffle l0 and the guide or diffusion plate 18 where thematerial is completely agitated and aerated with decomposition andBOD-reduction being the end result. As the air diffusion is continuous.the sewage in the tank is endlessly being mixed, settled, circulated,aerated and decomposed. In the aeration chamber 30 the sewage materialis continuously circulated as shown by the arrows 40, with portionsflowing from the chamber 30 to the chamber 32 through slots 14, andportions continually entering the bubble force chamber in the directionsof arrow 36.

It is the counterflow of currents 36 and 38 to meet and mix and beaerated between the inclined baffle and the diffusion plate 18 thatconstitutes the thorough aeration and decomposition of the sewage as aresult of the present apparatus and which has not before been possiblewith known sewage treating apparatus.

As the sewage becomes aerated and decomposed by the actions discussedabove, supernatant liquid and finely divided solids in suspension findtheir way to the comparatively quiet area 42 (see HO. 2) behind baffle 8in the settling chamber from where they flow from the septic tank viaoutlet 6.

As an additional and effective (but not necessary) portion of theapparatus a scum return arrangement may be provided communicatingbetween the settling chamber and the aeration chamber. This scum returnmay consist of a scum tray 44 positioned just below normal liquid level16 connected to a U- shaped piping system indicated generally at 46which returns the scum from the tray 44 to the aeration chamber 30. Thisscum return is accomplished by providing an air pressure conduit 48 fromthe main conduit 24 to the upright scum return pipe 50 which creates apartial vacuum in the horizontal scum return pipe 52 and ambient airpressure on the scum in the tray forces the scum through the pipes 52and 50 and out outlet 54 back into the aeration chamber forrecirculation.

Also as an additional feature, and as shown in FIGS. 1 and 2, a separatebaffle 20 can be provided laterally across the bottom of the tank tofacilitate mixing and aeration in the aeration chamber, but the presenceof baflle 20 is not necessary for a successful operation of theapparatus.

As indicated above the tank will likely be of metal or concreteconstruction, and while the converting apparatus such as the baffles 10and 20 and scum return 46 may be of metal construction and the conduitsof rubber, plastic or the like material, all of the converting parts(with the exception of the motor-compressor) may be constructed ofsuitable plastic or synthetic composition material which is strong,durable, corrosion-resistant and uneffected by pH conditions existing inthe tank. The use of plastic compositions may also result in a loweringof construction costs.

Of course the motor-compressor unit may be regulated as to the amount ofair pressure delivered to the diffuser, thereby determining the degreeof aeration and mixing of the sewage in the tank.

.The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. Apparatus for the conversion of a septic anaerobic sewage system toan aerobic system, wherein the anaerobic system to be converted includesa tank having an inlet and an outlet remote from the inlet and a baffleadjacent the outlet to prevent floating material from reaching theoutlet, the conversion apparatus comprising:

a baffle of adjustable length for mounting within and completely acrossthe tank spaced from the bottom thereof and inclined downwardly towardthe outlet end to divide the tank into an aerating chamber adjacent theinlet and a settling chamber adjacent the outlet whereby sewage may flowover and beneath the baffle to provide communication between saidaerating and settling chambers;

and a guide plate positioned adjacent the bottom portion of the baffleon the aerating chamber side, and spaced from said inclined bafile toprovide a passageway therebetween, said guide plate being spaced abovethe bottom of said tank, and air diffuser means to inject air into saidpassageway spaced above the bottom of the tank and a conduit connectingsaid air diffuser to an air compressor and motor mounted exteriorly ofthe tank, the issuing of air under pressure from the air diffuserstructure causing currents in the tank to move sewage from the aerationchamber and the settling chamber between said inclined baffle and saidair diffuser to effect aeration and intimate mixing of the sewage fromboth chambers.

2. Apparatus according to claim 1, wherein the said guide plate consistsof a diffuser plate extending completely across the tank, and said airdiffuser means is mounted on said diffuser plate, and further comprisingan air channel secured to the surface of the diffuser plate remote fromthe baffle structure, said conduit being connected to said air channel,and one or more longitudinal rows of apertures in the difiuser platewhereby air under pressure moves from the air channel through theapertures and into the space between the inclined baffle structure andthe diffuser plate.

3. Apparatus according to claim 1 further comprising means for returningscum from the surface of the sewage in the settling chamber to theaeration chamber.

4. Apparatus according to claim 3 wherein the scum returning meansconsists of a scum tray for positioning below the surface of the sewagein the settling chamber and a U-shaped conduit extending from the scumtray through the baffle structure and terminating in a scum outletformed above the sewage in the aerating chamber, and. a conduitconveying air under pressure to the U-shaped conduit to move by partialvacuum scum from the scum tray to the scum outlet.

5. Apparatus according to claim 2, further comprising a bottom bafflefor placement on the bottom of the tank and to project upwardly from thebottom of the tank and to extend completely across the tank and incllinetoward the inclined baffle structure, spaced substantially from theinclined baffle.

6. Apparatus according to claim 5, wherein said bottom baffle islongitudinally extensible to enable positioning in tanks of varyingwidth.

7. Apparatus according to claim 1 wherein said baffle of adjustablelength is formed in two sections longitudinally extensible with respectto each other, and an air diffuser structure positioned on each bafilesection and a conduit from each air diffuser structure to saidcompressor.

1. Apparatus for the conversion of a septic anaerobic sewage system toan aerobic system, wherein the anaerobic system to be converted includesa tank having an inlet and an outlet remote from the inlet and a baffleadjacent the outlet to prevent floating material from reaching theoutlet, the conversion apparatus comprising: a baffle of adjustablelength for mounting within and completely across the tank spaced fromthe bottom thereof and inclined downwardly toward the outlet end todivide the tank into an aerating chamber adjacent the inlet and asettling chamber adjacent the outlet whereby sewage may flow over andbeneath the baffle to provide communication between said aerating andsettling chambers; and a guide plate positioned adjacent the bottomportion of the baffle on the aerating chamber side, and spaced from saidinclined baffle to provide a passageway therebetween, said guide platebeing spaced above the bottom of said tank, and air diffuser means toinject air into said passageway spaced above the bottom of the tank anda conduit connecting said air diffuser to an air compressor and motormounted exteriorly of the tank, the issuing of air under pressure fromthe air diffuser structure causing currents in the tank to move sewagefrom the aeration chamber and the settling chamber between said inclinedbaffle and said air diffuser to effect aeration and intimate mixing ofthe sewage from both chambers.
 2. Apparatus according to claim 1,wherein the said guide plate consists of a diffuser plate extendingcompletely across the tank, and said air diffuser means is mounted onsaid diffuser plate, and further comprising an air channel secured tothe surface of the diffuser plate remote from the baffle structure, saidconduit being connected to said air channel, and one or morelongitudinal rows of apertures in the diffuser plate whereby air underpressure moves from the air channel through the apertures and into thespace between the inclined baffle structure and the diffuser plate. 3.Apparatus according to claim 1 further comprising means for returningscum from the surface of the sewage in the settling chamber to theaeration chamber.
 4. Apparatus according to claim 3 wherein the scumreturning means consists of a scum tray for positioning below thesurface of the sewage in the settling chamber and a U-shaped conduitextending from the scum tray through the baffle structure andterminating in a scum outlet formed above the sewage in the aeratingchamber, and a conduit conveying air under pressure to the U-shapedconduit to move by partial vacuum scum from the scum tray to the scumoutlet.
 5. Apparatus according to claim 2, further comprising a bottombaffle for placement on the bottom of the tank and to project upwardlyfrom the bottom of the tank and to extend completely across the tank andincline toward the inclined baffle structure, spaced substantially fromthe inclined baffle.
 6. Apparatus according to claim 5, wherein saidbottom baffle is longitudinally extensible to enable positioning intanks of varying width.
 7. Apparatus according to claim 1 wherein sAidbaffle of adjustable length is formed in two sections longitudinallyextensible with respect to each other, and an air diffuser structurepositioned on each baffle section and a conduit from each air diffuserstructure to said compressor.